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Discussion Starter #1 (Edited)
I have an ’08, Quad cab, Cab & Chassis, 4.10’s, 6 speed manual, 4x4. DRW. The truck runs differently, everyday. One day it will run really strong, like a raped-ape. The next time I drive, it will run like a Geo Metro. It has done this since it was new, but the difference has not been so severe. At 1400 miles, the motor would “stumble” when on the freeway with the cruise control set. I went to the dealer and they found “an internal short” and had to replace the ECM.

When it came home, I noticed that it had more timing rattle. My wife even commented on how it was noisier. It is not as loud as my (missed) ’97 12 valve. It ran consistently for about two weeks. It now is back and forth with its performance.

The Engine brake is now acting funny. When I go to start it, I turn the key on, wait for the preheat light to go out, start it, and set the high idle to 1000. I will hear a metal on metal “slam” near the turbo. I am guessing that it is the variable vane actuator slamming in one direction. After the motor runs for a few seconds, the Engine brake will engage. As soon as it engages, the motor will stumble, drop a few hundred rpm, disengage and reengage the EB, and return to the set RPM.

Two days ago, the engine brake worked great, really strong. Now it is very weak, if it turns on at all. I keep the EB switch turned on all of the time.

It has a custom (and heavy) welding bed with a 1300 pound Pipeliner 200D mounted. So every time I drive, I think it gets a workout. I took it from SLC, UT to Wendover, NV, with the cruise set at 76mph, 2450 rpms, and the overhead said I was getting 13.6 avg mpg. After doing it hand calculated, it figured out to be 12.38 mpg. It now has 2900 miles.

I use Lucas Fuel treatment on every other tank. The Boat anchor muffler is missing, but there are no other mods.

Please let me know if anyone else is having similar problems.
Thanks…….
 

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Your Turbo needs replaced.

They have changed the specs of it.

Also quit using the Lucas stuff.:beer
 

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I'm not sure about the Lucas. I used it religiously in my '00 and my big trucks, but have not run it in my 6.7. I think it's by far the best fuel additive for the older diesels. I know power service has a ulsd formula out now. I think the metal on metal sound you're hearing is probably the a/c compressor. Mine makes a pretty loud annoying clunk right after I start the truck. Turn the fan off next time before you start it in the morning and see if it still does it. I notice my e/b does not always sound the same. I'm not sure but I think it may have something to do with the:mad:regen:mad:. I notice sometimes mine will not turn on at idle, or it will turn off at about 1100 rpms. Sometimes it stays on right down to 700. All I can say is "how do it know?" hahaha.
 
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Oh and by the way the fuel mileage thing is so annoying. One time I'll take a trip and get 20mpg, and the next time I go I'll be lucky to get 15. I don't know what it is, but half the time I fill up I drive away wishing I would have kept my old 5.0 f250. What a p.o.s. that was. At least I already knew it sucked. I'm just waiting to remove the emission control junk. I've heard that helps tremendously.
 

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Discussion Starter #5 (Edited)
I checked inside the door, the truck was built on 07-07. I bought it in February. As for the A/C compressor, the slam sound is a lot louder and more violent than I have ever heard a compressor clutch do. The first time I heard it, it startled me so bad that I immediately shut the motor off, popped the hood and looked for damage.

I haven't had any check engine lights, even when the ECM shorted out. The only Check light was a "check gauges."

Has anyone else had similar acceleration and Engine Brake inconsistencies?

Cummins67= What specs have changed on the turbo? And why don't you like the Lucas?

Thanks to all for your replies.....
 

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Yeah, I hear that same freakin noise. I thought I was crazy at first, but now even my wife has heard it. It is not the A/C because I had it turned off this morining and it did it about 2 seconds after the motor started. It sounds silly, but it makes a sort of grunting, loud sort of noise. I am thinking it must be the VGT.
 

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I agree on the VGT. Mine does it as well and is doing it more often with 7k on the ticker. My exhaust brake is really inconsistent as well some times it doesn't do more than hum with little braking action, the ten minutes later, almost slides the tires in high gear!!
 

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Discussion Starter #8
Something new that I noticed today... I had the Exhaust Brake switch turned off, and when at a stop light, the EB engaged and the turbo spun up a little. I turned the switch on and then off, the EB stayed on. This is at 800 rpms. With the trans in neutral, clutch disengaged, I gave it some throttle. The EB disengaged, engine revved, settled back down, and EB engaged. This was all done with the switch turned off. (WTF!?......)

-Rhyno
 

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Discussion Starter #9
I just got back from the dealership. Wow! I finally got a Dodge Tech that knew what he was doing (Thanks Dan!! Larry H. Miller, Utah Auto Mall). The truck has never ran this strong.

Here is a summary. In the past, the truck has been very erratic. Would run faster and stronger at ½ to ¾ throttle than it would at full throttle. Every time I drove it, it was either a Geo Metro or a raped-Ape. Now it is even stronger.

I had EB inconsistencies, weird Regen cycles, poor mileage, etc (see my other posts). I told the performance stories again. They hooked up their computer and gave me the “instrument cluster flash.” I was told, “that the engine performance flash was up to date but there were communication problems between the ECM, Motor, and Instrument Cluster because of the missing Instrument Cluster Flash.”

When I had the ECM replaced, (about 6 weeks ago) either, the tech forgot to install the necessary flash for the Instrument Cluster or it was not available. I think that it was a lack of follow thru on the other Tech. After the ECM was replaced he forgot to make my keys work with the new computer. When I went to drive away, the truck would only idle. Nothing else.

Time will tell if this will stay consistent. I will also keep my eye on my MPGs. I’ll send an update about that later.

-Rhyno
 

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Discussion Starter #10
Just an update….

I took a 300-mile run, with about 30 miles of stop light fun. Half of the trip was at 70 mph, uphill with a climb of 4000ft in elevation. The return was 60-65 mph through a twisty canyon. The truck ran very consistent. Hand calculated miles per gal was 17.30. Overhead said 15.5 mpg. That’s my best mileage yet! Look at my posts earlier in the section for comparisons. What a big difference it makes to have a competent Service Tech.

-Rhyno
 

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I checked inside the door, the truck was built on 07-07. I bought it in February. As for the A/C compressor, the slam sound is a lot louder and more violent than I have ever heard a compressor clutch do. The first time I heard it, it startled me so bad that I immediately shut the motor off, popped the hood and looked for damage.

I haven't had any check engine lights, even when the ECM shorted out. The only Check light was a "check gauges."

Has anyone else had similar acceleration and Engine Brake inconsistencies?

Cummins67= What specs have changed on the turbo? And why don't you like the Lucas?

Thanks to all for your replies.....
Its not weather or not I like Lusas, But the indepentstudy I saw it reduced the lubercay of the fuel and in these 6.7's with the emmissions crap it can due strange things like make the soot stick to the sliding nozzle more in the turbo.:thumbsup
 

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Just an update….

I took a 300-mile run, with about 30 miles of stop light fun. Half of the trip was at 70 mph, uphill with a climb of 4000ft in elevation. The return was 60-65 mph through a twisty canyon. The truck ran very consistent. Hand calculated miles per gal was 17.30. Overhead said 15.5 mpg. That’s my best mileage yet! Look at my posts earlier in the section for comparisons. What a big difference it makes to have a competent Service Tech.

-Rhyno
Good to hear.:thumbsup
 

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Finding a knowledgable sevice tech for these trucks is, by far, the most inconsistant performance I have ever had with my truck!!!!
 

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Discussion Starter #14
Its not weather or not I like Lusas, But the indepentstudy I saw it reduced the lubercay of the fuel and in these 6.7's with the emmissions crap it can due strange things like make the soot stick to the sliding nozzle more in the turbo.:thumbsup
Cummins67- Where did you see the independent study on the Lucas? I would like to know more about this?
-Rhyno
 

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Discussion Starter #15
Just an update and another question.

As for the quicker acceleration at partial throttle, versus full throttle, I have figured It has to do with the regen process.

Now I have the DPF delete and it still is erratic. Not as bad or extreme as before. The Geo Metro syndrome is not as bad, but the raped ape is not as strong. I am running the 1016CDS and it will roll coal in extreme sometimes and zero other times.

It is still very inconsistent.

I have suspected the quality of the fuel, also the fuel additives, (Power Service, and Lucas), but am unsure if it is the programming.

It is more stable than it used to be, but still not the same everyday.

Can anybody enlighten me???!!

Thanks..... Rhyno
 

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Discussion Starter #16
Am I the only one having weird or inconsistent performance?
 

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In all of my reading on this forum I dont think I have seen anything quite like your problem, there has got to be something wrong! I have only had my truck about 4 months and did my deletes right away and the truck runs awesome every time! BTW I have heard from quite few people that Garff Dodge has the best service for these trucks in the state, no personal experince just what I heard.
 

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Just an update and another question.

As for the quicker acceleration at partial throttle, versus full throttle, I have figured It has to do with the regen process.
I know nothing about how these truck's computers are set up, but many times, on engines, there is a difference in the way the computer fuels and adjusts the timing of an engine, at wide open throttle vs. part throttle.

At part throttle, the computer may be looking at all of the cirtical engine sensors, and fine tuning the air/fuel ratio & timing, based on what those sensors are reading. In other words, the computer calculates what adjustments to make, on it's own, based on the sensor readings. It may make many adjustments on the fly, which optimizes the engine's performance.

At WOT, the computer will ignore some of the sensors, in favor of just looking up fueling and timing tables that are pre-programmed and written in the file, based on just a couple key engine sensors. The partical throttle pulls will feel stronger because the adjusting on the fly, by the computer, results in more accurate engine management, but the WOT fueling tables may very well be a little richer (cooler), which results in a 'safer for the engine longevity' but not optimal for performance result.
 

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My truck is VERY INCONSISTANT runs like a grayhound one day and a bassethound the next. When I put my boost fooler on it helped alot. I think its the turbo. I alsohave the loud clunk when I first start my truck I think its the egr valve slaming one way or the other
 
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